Rename default -> initial style and use singletons.

Source/core/css/resolver/StyleResolver.h

Index: Source/core/css/resolver/StyleResolver.h
diff --git a/Source/core/css/resolver/StyleResolver.h b/Source/core/css/resolver/StyleResolver.h
index 65af49634c0657f4eae9bd64c81a1321cfb36268..048856545937c837e12e906c36d55045d3f5b44f 100644
--- a/Source/core/css/resolver/StyleResolver.h
+++ b/Source/core/css/resolver/StyleResolver.h
@@ -115,7 +115,6 @@ public:
     PassRefPtr<LayoutStyle> pseudoStyleForElement(Element*, const PseudoStyleRequest&, LayoutStyle* parentStyle);
 
     PassRefPtr<LayoutStyle> styleForPage(int pageIndex);
-    PassRefPtr<LayoutStyle> defaultStyleForElement();
     PassRefPtr<LayoutStyle> styleForText(Text*);
 
     static PassRefPtr<LayoutStyle> styleForDocument(Document&);
@@ -205,6 +204,8 @@ public:
     void addTreeBoundaryCrossingScope(ContainerNode& scope);
 
 private:
+    PassRefPtr<LayoutStyle> initialStyleForElement();
+
     void initWatchedSelectorRules(const WillBeHeapVector<RefPtrWillBeMember<StyleRule>>& watchedSelectors);
 
     // FIXME: This should probably go away, folded into FontBuilder.